RDS: use rds_send_xmit() state instead of RDS_LL_SEND_FULL

In Transport indepedent rds_sendmsg(), we shouldn't make decisions based
on RDS_LL_SEND_FULL which is used to manage the ring for RDMA based
transports. We can safely issue rds_send_xmit() and the using its
return value take decision on deferred work. This will also fix
the scenario where at times we are seeing connections stuck with
the LL_SEND_FULL bit getting set and never cleared.

We kick krdsd after any time we see -ENOMEM or -EAGAIN from the
ring allocation code.

Signed-off-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
diff --git a/net/rds/send.c b/net/rds/send.c
index b0acd45..a081a64 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -1123,8 +1123,9 @@
 	 */
 	rds_stats_inc(s_send_queued);
 
-	if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
-		rds_send_xmit(conn);
+	ret = rds_send_xmit(conn);
+	if (ret == -ENOMEM || ret == -EAGAIN)
+		queue_delayed_work(rds_wq, &conn->c_send_w, 1);
 
 	rds_message_put(rm);
 	return payload_len;
@@ -1180,8 +1181,9 @@
 	rds_stats_inc(s_send_queued);
 	rds_stats_inc(s_send_pong);
 
-	if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
-		queue_delayed_work(rds_wq, &conn->c_send_w, 0);
+	ret = rds_send_xmit(conn);
+	if (ret == -ENOMEM || ret == -EAGAIN)
+		queue_delayed_work(rds_wq, &conn->c_send_w, 1);
 
 	rds_message_put(rm);
 	return 0;